
Lesson 8 - Lights, Buoys & Beacons
Introduction
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Lights, buoys, and beacons are essential tools for safe navigation.
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They guide mariners through channels, around hazards, and into harbors.
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Understanding these aids is key to confident sailing.
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Key factors affecting visibility:
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Brightness of the light (measured in candelas).
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Height of the light and observer’s eye.
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Weather conditions (fog, rain, or refraction).
Example: Pharos of Alexandria, visible up to 35 miles.
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Light Characteristics
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Fixed Lights: Steady and constant.
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Flashing Lights: Dark intervals are longer than flashes.
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Occulting Lights: Light is visible longer than darkness.
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Morse Code Lights: Used for special warnings (e.g., “Mo(U)” for exclusion zones).
Sector & Directional Lights
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Sector Lights: Different colors indicate safe passage or hazards.
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Example: White = safe, Red = danger.
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Directional Lights: Focused beams guide vessels along precise paths.​
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Light Range and Visibility
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Geographical Range: Distance over the horizon depends on height.
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Meteorological Factors:
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Fog and rain reduce visibility.
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Atmospheric refraction can extend the visible range by up to 10%.
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Buoyage Systems
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IALA A:
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Red = Port
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Green = Starboard
IALA B:
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Red = Starboard
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Green = Port
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Cardinal Marks
Cardinal marks indicate safe water relative to hazards.
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North: Cones point up, continuous flashes.
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East: Three flashes = "Three o’clock."
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South: Six flashes + long flash = "Six o’clock."
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West: Nine flashes, resembling a “waist.”
Mnemonic: Use the cone shapes to remember directions.​



​Preferred Channel Marks
Indicate the main channel at junctions:
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Red with green band: Preferred channel is to starboard.
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Green with red band: Preferred channel is to port.​

​Miscellaneous Marks
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Safe Water Marks: Red and white stripes, signal clear water ahead.
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Isolated Danger Marks: Black and red, mark hazards.
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Special Marks: Yellow, indicate pipelines, racecourses, or military zones.
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Fog Signals
Used during low visibility (fog or mist). Types of fog signals:
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Horns.
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Bells.
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Whistles.
Ensure safety when lights are not visible
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Summary & Tips
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Lighthouses use light patterns to communicate.
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Buoys follow IALA A or B systems—know your region.
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Cardinal and sector lights help navigate hazards and channels.
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Fog signals provide safety in poor visibility.
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Mastering these tools ensures confident and safe sailing.
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